FRANKFORT, Ky. — A federal appeals court on Monday vacated what it called a “well-below-guidelines” prison sentence for the man who tackled U.S. Sen. Rand Paul outside his Kentucky home, ordering a resentencing for the attack that broke the lawmaker’s ribs.

The three-judge panel of the 6th U.S. Circuit Court of Appeals said it found “no compelling justification” for Rene Boucher’s 30-day sentence.

The ruling came in response to an appeal by federal prosecutors who had argued that 21 months would have been more appropriate. The appeals court took no position on an appropriate sentence, saying the federal district court judge retains “ample discretion.”

The Republican senator was tackled by Boucher in late 2017 when Paul’s then-neighbor became angry over lawn maintenance at the senator’s home.

The attack broke several of Paul’s ribs, damaged a lung and led to bouts of pneumonia. Part of his damaged lung was removed in a recent surgery. Earlier this year, Paul had hernia surgery in another procedure connected to the assault.

Boucher pleaded guilty to assaulting a member of Congress and served his 30-day sentence at a federal prison in Illinois.

“We believe that the trial judge got it right the first time,” Boucher’s attorney, Matt Baker, said by phone Monday. “And now it looks like we’re going to be back at square one with regard to sentencing. It’s just very disappointing to have gone through this entire process and to have come full circle.”

Baker said he’s considering an appeal to the U.S. Supreme Court.

Paul’s office did not immediately comment on Monday’s ruling. Prosecutors involved in the appeal did not immediately reply to an email seeking comment.

Paul sued Boucher, and a jury in Bowling Green, Kentucky, awarded the lawmaker and former presidential candidate more than $580,000 in damages and medical expenses. Boucher has since sold his home next door to the senator.

In sentencing Boucher, U.S. District Judge Marianne Battani said she surmised the attack to be a “dispute between neighbors” and an “isolated incident,” not motivated by politics. On Monday, the appeals court panel said the sentencing judge “gave little weight to the need to promote general deterrence.”

“Accepting that Boucher’s attack did not appear to be politically motivated, Paul’s status as a national political figure is still relevant to the broader ‘goals of societal deterrence’ served by Boucher’s sentence,” Judge Jane B. Stranch wrote in the appeals court opinion.

The sentencing judge also noted Boucher’s background, including his education, medical practice, community reputation, church involvement, status as a military veteran and lack of criminal history. Stranch said those factors are “almost all disfavored as grounds for a below-guidelines sentence.”

“To prioritize a defendant’s education, professional success and standing in the community would give an additional leg up to defendants who are already in a privileged position,” Stranch wrote. “Indigent defendants are less likely to impress a sentencing court with their education, employment record or local reputation. But they are no less deserving of a reasonable and compassionate sentence.”

Paul testified during his civil trial that he feared for his life as he struggled to breathe after Boucher, an anesthesiologist, slammed into him in their upscale Bowling Green neighborhood.

Paul testified that he got off his riding mower to pick up a stick and was straightening up when Boucher hit him from behind. Paul said he was wearing noise-canceling headphones and didn’t hear Boucher coming toward him.

During his testimony, Boucher acknowledged he wasn’t thinking rationally and called it “two minutes of my life I wish I could take back.”